An integrated circuit may include logic circuits of n-channel metal oxide semiconductor (NMOS) transistors and p-channel metal oxide semiconductor (PMOS) transistors, and it may be desirable to form the logic circuits to operate at a high speed. The integrated circuit may also include memory cells which have NMOS transistors in each cell, and it may be desirable to form the memory cells so as to reduce leakage current. It may further be desirable to maintain fabrication costs of the integrated circuit below a desired limit.